ASoC: Intel: Skylake: Fix default dma_buffer_size

If the dma_buffer_size is not defined in topology, fix it to 2ms default
value to make backward compatible.

Fixes: f6e6ab1d16 ("ASoC: Intel: Skylake: Fix dma buffer size calculation")
Signed-off-by: Subhransu S. Prusty <subhransu.s.prusty@intel.com>
Acked-By: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/intel/skylake/skl-messages.c

@@ -540,6 +540,14 @@ static void skl_setup_cpr_gateway_cfg(struct skl_sst *ctx,
 	cpr_mconfig->gtw_cfg.dma_buffer_size =
 				mconfig->dma_buffer_size * dma_io_buf;
 
+	/* fallback to 2ms default value */
+	if (!cpr_mconfig->gtw_cfg.dma_buffer_size) {
+		if (mconfig->hw_conn_type == SKL_CONN_SOURCE)
+			cpr_mconfig->gtw_cfg.dma_buffer_size = 2 * mconfig->obs;
+		else
+			cpr_mconfig->gtw_cfg.dma_buffer_size = 2 * mconfig->ibs;
+	}
+
 	cpr_mconfig->cpr_feature_mask = 0;
 	cpr_mconfig->gtw_cfg.config_length  = 0;